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2 SchedulingA schedule is the conversion of a project action plan into an operating timetableIt serves as the basis for monitoring and controlling project activityTaken together with the plan and budget, it is probably the major tool for the management of projects

3 SchedulingIn a project environment, the scheduling function is more important than it would be in an ongoing operationProjects lack the continuity of day-to-day operations and often present much more complex problems of coordination

4 SchedulingThe basic approach of all scheduling techniques is to form a network of activity and event relationshipsThis network should graphically portray the sequential relations between the tasks in a projectTasks that must precede or follow other tasks are then clearly identified, in time as well as function

5 SchedulingSuch networks are a powerful tool for planning and controlling a project and have the following benefits:It is a consistent framework for planning, scheduling, monitoring, and controlling the projectIt illustrates the interdependence of all tasks, work packages, and work elementsIt denotes the times when specific individuals must be available for work on a given task

6 Scheduling Network benefits (cont.):It aids in ensuring that the proper communications take place between departments and functionsIt determines an expected project completion dateIt identifies so-called critical activities that, if delayed, will delay the project completion timeIt identifies activities with slack that can be delayed for specific periods without penalty

7 Scheduling Network benefits (cont.):It determines the dates on which tasks may be started - or must be started if the project is to stay on scheduleIt illustrates which tasks must be coordinated to avoid resource timing conflictsIt illustrates which tasks may run, or must be run, in parallel to achieve the predetermined project completion dateIt relieves some interpersonal conflict by clearly showing task dependencies

8 Network Techniques: PERT and CPMWith the exception of Gantt charts, the most common approach to scheduling is the use of network techniques such as PERT and CPMThe Program Evaluation and Review Technique was developed by the U.S. Navy in 1958The Critical Path Method was developed by DuPont, Inc during the same time period

9 Network Techniques: PERT and CPMPERT has been primarily used for research and development projectsCPM was designed for construction projects and has been generally embraced by the construction industryThe two methods are quite similar and are often combined for educational presentation

10 TerminologyActivity - A specific task or set of tasks that are required by the project, use up resources, and take time to completeEvent - The result of completing one or more activities. An identifiable end state occurring at a particular time. Events use no resources.Network - The combination of all activities and events define the project and the activity precedence relationships

11 TerminologyPath - The series of connected activities (or intermediate events) between any two events in a networkCritical - Activities, events, or paths which, if delayed, will delay the completion of the project. A project’s critical path is understood to mean that sequence of critical activities that connect the project’s start event to its finish event

12 Terminology An activity can be in any of these conditions:It may have a successor(s) but no predecessor(s) - starts a networkIt may have a predecessor(s) but no successor(s) - ends a networkIt may have both predecessor(s) and successor(s) - in the middle of a networkThe interconnections depend on the technological relationships described in the action plan

13 Drawing NetworksActivity-on-Arrow (AOA) networks use arrows to represent activities while nodes stand for eventsActivity-on-Node (AON) networks use nodes to represent activities with arrows to show precedence relationshipsThe choice between AOA and AON representation is largely a matter of personal preference

15 Gantt ChartsThe Gantt chart shows planned and actual progress for a number of tasks displayed against a horizontal time scaleIt is an effective and easy-to-read method of indicating the actual current status for each set of tasks compared to the planned progress for each item of the setIt can be helpful in expediting, sequencing, and reallocating resources among tasksGantt charts usually do not show technical dependencies

17 Gantt Charts There are several advantages to the use of Gantt charts:Even though they may contain a great deal of information, they are easily understoodWhile they may require frequent updating, they are easy to maintainGantt charts provide a clear picture of the current state of a projectThey are easy to construct

18 SummaryScheduling is particularly important to projects because of the complex coordination problemsThe network approach to scheduling offers a number of specific advantages of special value for projectsCritical project tasks typically constitute fewer than 10 percent of all the project tasks

19 SummaryAlthough research indicates technological performance is not significantly affected by the use of PERT/CPM, there did seem to be a significantly lower probability of cost and schedule overrunsNetwork techniques can adopt either an activity-on-node or activity-on-arc framework without significantly altering the analysis

20 SummaryNetworks are usually constructed from left to right, indicating activity precedence and event times as the network is constructedGantt charts are closely related to network diagrams, but are more easily understood and provide a clearer picture of the current state of the project